Conventionally, there have been known a solid-state image sensing device that converts light received thereby into electric signals and then outputs them as picture signals, and a camera such as a digital still camera that displays picture signals obtained from the solid-state image sensing device, as still pictures. Recently, in cameras with such a solid-state image sensing device, it has been required to improve image quality and functions, and the density of pixels has been increasing more and more.
In order to increase the speed at which picture signals are outputted in such a solid-state image sensing device, a driving method has been proposed in which pixels from which signal charges are to be read out are reduced in number. The number of pixels included in the output picture signals thereby is reduced. For example, JP11(1999)-234688A discloses a driving method in which, for instance, with three pixels arranged in the horizontal direction forming one block, signal charges of two pixels (two pixels arranged on right and left sides) other than the pixel located in the middle in each block are mixed together in a solid-state image sensing device while a signal charge of the pixel located in the middle in each block is mixed with that of the pixel located in the middle in the block adjacent thereto. Thereby the number of pixels arranged in the horizontal direction that are included in picture signals to be outputted from the solid-state image sensing device is reduced.
However, in reducing the number of the pixels arranged in the horizontal direction to one-third, a component corresponding to one third of the sampling frequency used when all the pixels output signal charges is added to the DC component of signals as aliasing errors. In the solid-state image sensing device employing the above-mentioned conventional driving method, the component corresponding to one third of the sampling frequency is not zero (see FIG. 27). This causes moire or aliases to be generated and thereby deteriorates the quality of images formed with the output picture signals, which has been a problem.